A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
Kilojoules to Watt hours
Convert Kilojoule (kJ) to Watt-hour (Wh) instantly with an exact formula, conversion table, and FAQ.
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Convert kilojoules (kJ) to watt hours (Wh) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Wh = kJ × 0.2777777778
Results update instantly for Kilojoules to Watt hours conversions.
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Formula
Wh = kJ × 0.2777777778
kJ = Wh × 3.6
Conversion table
| 1 kJ | 0.277778 Wh |
| 5 kJ | 1.388889 Wh |
| 10 kJ | 2.777778 Wh |
| 20 kJ | 5.555556 Wh |
| 50 kJ | 13.888889 Wh |
| 100 kJ | 27.777778 Wh |
| 500 kJ | 138.888889 Wh |
| 1000 kJ | 277.777778 Wh |
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How the formula works
Both kilojoule and watt-hour measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in kilojoules by 0.2777777778 to get watt hours. To reverse the conversion, multiply a watt-hour value by 3.6 to get back to kilojoules.
Frequently asked questions
What is Kilojoule (kJ)?
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
What is Watt-hour (Wh)?
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
How do I convert kilojoules to watt hours?
Multiply the kilojoule value by 0.2777777778 to get the equivalent in watt hours. For example, 5 kJ × 0.2777777778 = 1.388889 Wh.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 0.2777777778 is an exact, non-rounded value.
Can I convert watt hours back to kilojoules?
Yes. Divide the watt-hour value by 0.2777777778, or multiply it by 3.6, to get kilojoules.
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About converting kilojoules to watt hours
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States. A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Use this calculator to move between kilojoules and watt hours accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.